Seam for woven papermaking fabrics

ABSTRACT

A seam for joining opposite ends of a woven fabric to form a loop or belt in which some warps of the fabric terminate along the seam in a pattern of the type having the ends of three adjacent warps arranged in a three-warp configuration along first, second and third zones, with the third zone between the first and second, and other warps between those arranged in the three-warp pattern terminate along zones located outside of the first three zones.

United States Pate lnventor Herbert C. Haller Appleton, Wis.

Appl. No. 691,414

Filed Dec. 18, 1967 Patented Jan. 5, 1971 Assignee Appleton Wire Works Corp.

Appleton, Wis.

a corporation of Wisconsin SEAM FOR WOVEN PAPERMAKING FABRICS 5 Claims, 11 Drawing Figs.

0.8. CI... 245/10 Int. Cl B2lf27/00 Field of Search 162/348, lFM; 139/383, 425.5; 245/10 References Cited UNITED STATES PATENTS 3,060,547 10/1962 MacBean l62/IFM 3,366,355 1/1968 Haller 245/10 FOREIGN PATENTS 1,360,680 6/1963 France 162/lFM Primary Examiner-Reuben Friedman Assistant Examiner-T. A. Granger Attorneys-Donald G. Casser and Arthur H. Seidel ABSTRACT: A seam for joining opposite ends of a woven fabric to form a loop or belt in which some warps of the fabric terminate along the seam in a pattern of the type having the ends of three adjacent warps arranged in a three-warp configuration along first, second and third zones, with the third zone between the first and second, and other warps between those arranged in the three-warp pattern terminate along zones located outside of the first three zones.

PATENTEUJAN 5 |97| SHEET 1 0F 4 INVENTOR 55 M- A EFr A HERBERT C. HALLER ATTORNEY PATENTEDJAN 5m- 3552591 SHEET 2 OF 4 INVENTOR HERBERT C. HALLER BY%M ATTORNEY PATENIEBJAN 519w 3552.691

sum 3 BF 4 INVENTOR HERBERT C. HALLER ATTORNEY PATENTEU JAN 5 3,552,691

SHEET a 0F Q INVENTOR HERBERT c. HALLER ATTORNEY 1 SEAM FOR WOVEN PAPERMAKING FABRICS BACKGROUND OF THE INVENTION 1. Field This invention relates to a seam for fabric woven of metal or plastic warps and wefts in which the warps terminate along a hand of seam-wefts in a prescribed pattern.

2. Description of the Prior Art I Fabrics used for papermaking, such as the paper-forming belt on a Fourdrinier machine or covers on press rolls of a paper making machine, are commonlywoven asa length of fabric with metal and/or plastic warps and wefts and the opposite ends of the length of fabric are joined along a seam to form an endless belt or loop. One of the common prior art seam constructions utilizes a random distribution of the warp ends across the seam area. It has been found that a seam of this construction results in a relatively weak seam, having a low tensile strength per inchv of seam width that often approximates only 30 percent to 40 percent the tensile strength of the woven fabric,

A newer development is shown in my copending application Ser. No. 495,426 now US. Pat. No. 3,366,355 in which a seam construction utilizes a controlled pattern for the warp ends wherein the ends of one warpare joined along a first zone along the scam, the ends of the adjacent warp are joined along a second zone across the seam spaced from the first zone, and each end of the third adjacent warp is. joined along a third zone positioned intermediate the first and second zones. This type of seam construction, sometimes denominated a threezone or three-row seam, will be hereinafter referred to as a three-warp pattern since the warps in groups of three are arranged in the specified manner across the-width of the seam. 'Efhis seam construction, it was found, developed very high mam strengths approximating 75 percent or more the tensile :trength of the woven fabric, a significant change in seam zrength on the order of four or five times that of the prior art I andom seam described above.

SUMMARY or THE INVENTION The present invention relates'to an improvement in the three-warp seam pattern as described above, in which the three-warp pattern is used with some of the warps across the 2am width, but there are other warps between each group of three warps arranged in said pattern that have their ends terminating along different zones. Specifically, according to the present invention, some of the warps of the fabric terminate along the seam in the three-warp pattern'but the other warps terminate along other zones positioned outside the three zones used for the three-warp pattern. A controlled pattern is also employed for the ends of such other warpsso that they terminate in a regular pattern along the other zones of the seam. V hen there is an even number of such other warps between the three-warp patterns, there is an even number of other zones along which warp ends terminate and the other zones are positioned equally on either side of the three zones used for the three-warp pattern; on the other hand, when there is an odd number of the other warps between each three-warp roup, the other zones are arranged so that there is one more 2 I seen that it would be highly usefulto provide a seam construction in which the adverse effects onj'paper marking dueto failure along the seam can be minimized.

Among the objects of this invention are to provide a new DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates in perspective a Fourdrinier belt formed of woven fabric; FIG. 2 is a longitudinal sectional view of the belt of FIG. 1 showing a warp configuration; and FIG. 3 is a transverse sectional view of the belt of FIG. 1 showing a weft configuration.

such other zone on one side of the three zones than on the other.

It has been found that the new seam construction of this intention incorporates a substantial measure of the important strength advantage of the three-warp pattern relative to a random seam construction, but at the same time, it provides an additional advantage of smaller hole formation in the event there is a failure at the joints between warp ends terminating along the seam zone. If there is such a failure with the present seam construction, there is less deleterious marking of the paper sheet being formed on the paper-making belt. Since it is reasonable to expect that any seam construction may eventually develop failures, principally due to abrasion, and such I failures are most likely to occur at the positions in which the varp ends are joined to one another along the seam, it can be FIG. 4 shows a portion of a precrimped seam-weft used in i the seams of this invention.

FIGS. 59 illustrate various embodiments of the seam construction of this invention in which FIG. shows a seam utilizing five adjacent warps arranged in the'manner specified; FIG. 6 shows a seam utilizing a seven-warp pattern; FIG. 7 shows a seam with four warps; FIG. 8 illustrates a seam with six warps and FIG. 9 shows an eight warp version of a seam of this invention.

FIGS. 10 and 11 illustrate two seams for comparison purposes, FIG. 10 illustrating a threewarp pattern seam construction as in my US. Pat. application-495,426, and FIG. 11 showing a random seam construction.

DESCRIPTION OF PREFERRED EMBODIMENTS Figures l 4 5 FIGS. l-3 illustrate a typical use of a seam construction of this invention. An endless belt 10 is shown such as may be used as the papermaking surface on a Fourdrinier machine. The belt 10 is formed from a length of fabric having its opposite ends joined along a seam llfThe fabric includes warps l2 interwoven with wefts 13, .the .warps extending longitudinally and the wefts transversely of the fabric. The warps and wefts are woven together on a loom in the manner described below. To distinguish them from the seam-wefts described hereafter, the wefts 13 which are woven with the warps on a loom will be referred to as the wovenwefts. After the length of fabric is woven, the warps '12 projectZbeyond-the last woven weft 13at each end of the length of fabric and the extending warp ends are joined along the seam 11 in the manner described hereunder. During the weaving of the fabric, the warps 12 become crimped as illustrated in FIG. 2 so as to have knuckles l4, and the woven wefts 4 become crimped 'so as to have knuckles 15 as indicated in FIG. 3. The warps 12 and woven weft 13 can be woven together in any repeated pattern used in the papermaking field, such asa plain weave" in which each weft passes successively over one warp and under the next warp, or in the so-called twill (sometimes referred to as the semitwill) weave in which each weft passes over two warps and under the next warp, or in a pattern such as that described in US. Pat. 3,143,150 in which each weft passes alternately over one pair of warps and then under the next pair of warps. Seams of this invention can be used with fabric of any of these weaves, as well as other weaves which may be employed.

Fabrics with which seams of this invention are primarily intended to be used have warp and weft threads which are metal or plastic, either in the form of wire, monofilaments, or thin threads twisted into cable form. The terms warp and weft are employed herein in the usual sense in which they are used in the Fourdrinier weaving art in which, when fabric of a specified type is woven on a loom, the individual warps are strung longitudinally of the loomthrough a set of heddles and are raised and lowered by movement of the heddles in accordance with the preselected weave pattern to form what are termed triangular sheds. The weft material is carried in a shuttle that is caused to move transversely of the loom to pass through the sheds formed by raising and lowering the warps, after which a lay is actuated to beat the wefts into the apex of the sheds or the beat line.

The ensuing examples 1-5 describe five seam construcfabric. As shown in FIG. 4, a typical seam weft 21 is crimped to have knuckles a which correspond to the knuckles 15 in the woven wefts 13. One way of establishing this preerimping is to weave a length of fabric using the same pattern and spacing of warp and wefts as is desired in the final belt, remove the fabric from the loom and in some cases (when using plastic materials) heat set the fabric, and then take out some of the wefts for use as seam wefts; in this manner, the seam wefts will have the same physical configuration as the woven wefts in the completed belt. FIGS. 511 depict fabric segments joined with various seams, each drawing showing two sets of warps to illustrate various patterns, it being understood that the warp patterns of FIGS. 5l0 are repeated across the entire width of the respective seams.

EXAMPLE 1 FIG. 5 illustrates a seam of this invention in which five warps terminate across the seam in a prescribed relationship, and this is repeated across the width of the seam. The seam 20 is arranged across a plurality of seam wefts 21 which are shown in solid lines in FIG. 4 to distinguish them from the woven wefts 13 depicted in dashed lines. Warps 25-29 are arranged to have their ends terminate along the seam, the terminal joints being shown by circles. Where a circle is shown, the ends of the warps butt together either along a seam weft or in the space between seam wefts.

To construct the scam, the plurality of the seam wefts 21 are spaced-apart on a work surface to correspond to the spacing of the woven wefts 13 so that the seam 20 will properly fit in with the balance of the fabric. After the fabric is woven, the warps have ends which protrude beyond the last woven weft along each end, these protruding warp ends are joined along the seam in a prescribed pattern, and that portion of each warp which crosses seam wefts is woven therewith in the same pattern in which the warps were woven with the woven wefts .13 on the loom.

The warp 25 has its ends terminating along a first zone A of the seam, warp 26 (adjacent to warp 25) has its ends terminating along a second zone B spaced from zone A, and the ends of warp 27, (adjacent to warp 26) terminate along zone C positioned midway between zones A and B. This arrangement of warps 25-27 is as shown in my copending U.S. Pat. application Ser. No. 495,426, and will be referred to hereinafter as the three-warp pattern. It can also be called a three-row seam E is spaced from zone B a distance equal to the spacing between zones B and C.

Warps 25a, 26a and 27a have their ends arranged in the three-warp pattern of warps 25, 26 and 27. The pattern is repeated along the width of the seams so that there is a warp 28 and a warp 29 between each three-warp pattern of warps 25, 26 and 27, and each warp 28 and 29 terminates along zone D .or zone E respectively.

In FIGS. 4--11, the ends of warps which terminate in a three-warp pattern are depicted with small circles and the ends of other warps terminating along zones outside of zones A, B and C are shown with solid round dotsin order to more clearly point out the arrangement of the terminal points of the other warps relative to those of the warps in each three-warp pattern. At the circles or dots, case maybe, the ends of u wurp nrc severed so us to butt together either o'n Iop' uI n' seam weft or in the space between seam wefts; normally this is sufficient finalizing of the seam and the butted warp ends need not be joined to each other. In someinstances it is desirable to,

apply a resin or adhesive over the entire ,seam area to fix the warp ends more firmly in position.

A seam according to FIG. 5 was constructed to join a fabric having 36 warps per inch of width and 32 woven-wefts per inch of length, woven in the plain weave. The fabricwas woven with plastic monofilaments for the warps and wefts, the plastic being a polyester, polyethylene terephthalate. The

monofilaments had a diameter of 0.0157". The fabric itself had a tensile strength of 450 pounds/inch of width. (The same fabric is also used with the seams in the following examples.)

EXAMPLE 2 FIG. 6 illustrates a second seam -30 of this invention whichis similar to scam 20 except that it includestwo additional other zones along which terminate the ends of other warps between the warps in the three-warp patterns. In the seam 30, warps 2529 are arranged to have ends which terminate along zones A through E, but two other adjacent warps,-.warps 31 and 32, are positioned between each three-warp patt'ern; The warps 31 and 32 have their ends terminating along zones'F and G respectively which are positioned outside of zonesD and E respectively. The spacing between each zone AG is approximately the same, that is within one-to three seam wefts.

A seam 35 formed in the same fabric as in example 1 showed a strength of 274 pounds/inch of seam-.width before breakage occurred.

EXAMPLE 3 A third seam of the present invention is shown inFIG. 7 comprising a plurality of spaced seam wefts 21 arranged to define a seam 35 which includes two groups of warps '25, 26,

27, arranged in the three-warp pattern-of the previous seams,

in the illustrated segment of fabric. A single warp, warp 36, also terminates between each three-warp pattern and the warp 36 has its ends arranged to terminate along a zone D positioned alongside zone B of the seam and spaced therefrom at a distance equal to the spacing between the other three zones of the seam construction. A seam 35'formed in a fabric of the same type as in example 1 showed a breaking strength of 309 pounds/inch of seam width.

EXAMPLE 4 spacing between zones A-F is approximately equal. A seam 40' constructed with the same fabric as the preceding examples showed a breaking strength of 300 pounds/inch of seam width.

EXAMPLE 5 The seam 45 shown in FIG. 9 also includes two groups of warps 25-27 arranged in the three-warp pattern to have their ends terminate along zones A, B and C. In addition, other warps 46-50 are arranged to terminate between each threewarp pattern in the manner shown in the drawing wherein warp 46 has its ends terminating along zone H, which is the zone most remote from zone C, warp 47 has its ends terminating along zone G spaced outwardly of zone E, the ends of warp 48 terminate along zone F, the ends of warp 49 terminate along zone E, and the ends of warp 50 terminate along zone D. The spacing between zones A-H is approximately equal. A seam 45 constructed with the fabric used in the preceding examples showed a breaking strength of 244 pounds/inch of scam width.

As shown in FIGS. 7-9, when there is an odd number of "zones (D-H) in addition to the three zones A, B and C of the three-warp patterns, the other zones are distributed so there is one more other zone on one side of the three zones A-C than on the other side thereof.

EXAMPLES 6 and 7 For the purposes of comparison, examples 6 and 7 illustrate two prior art seam constructions. Example 6, illustrated in FIG. 10, is a seam employing the three-warp pattern across the entire width of the seam. Warps 25, 26 and 27 are arranged across a plurality of seam wefts 21 to provide the seam 51 wherein adjacent warps terminate alternately along zones A, B and C, with the three zones being spaced approximately equidistant from each other. A seam 51 using the same fabric in the preceding examples showed a breaking strength of 350 pounds/inch of scam width. The seam of example 7 is illustrated in FIG. 11 and comprises a typical prior art arrangement wherein the warp ends are arranged to terminate randomly across the seam wefts. Thus, there is no pattern to the arrangement of warp ends as was true with the seams of the preceding examples. The seam 52 shown in FIG. 11 has a plurality of spaced warps 53 which terminate along the seam wefts 21. A seam 52 used in the same fabric as in the preceding examples exhibited a tensile strength of 179 pounds/inch of seam width.

CONCLUSION In order to facilitate the comparison of the performance of each of the foregoing seams, Table l is herein presented to summarize the strength data reported in the preceding examples.

TABLE I Seam strength as percent of fabric Seam construction: Seam strength, breaking point strength Example 1 302 pounds/inch of seam width. 67 Example 2... 274 pounds/inch of seam width 61 Example 3... 309 pounds/inch of seam width... 69 Example 4.. 300 pounds/inch of seam width. 67 Example 5. 244 pounds/inch of seam width. 54 Example 6. 350 pounds/inch of seam width. 78 Example 7 179 pounds/inch of seam width. 40

The data on Table 1 demonstrate that the seam constructions of this invention, examples 1-5, have a high seam strength relative to the fabric strength, generally on the order of 54% to 69%, which is substantially higher than the strength of a random seam construction as in example 7 that was only 40 percent as strong as the fabric itself. The illustrative examples of the new seams of this invention showed seam strengths compared to random seams in that they can more nearly approach the strength of the fabric.

The new seams of this invention, however, are not as strong as the three-warp seam shown in example 7 and they generally exhibit a seam strength that was from 70 percent to 88 percent that of the three-warp or three-row seam of example 7.'However, in comparison to the three-warp pattern seam of example 7, the new seams of this invention have an important advantage relating to hole formation in event of a failure along warp ends terminating across the various zones of the seam.

Specifically, the new controlled pattern seams offer greater assurance against development of holes sufficiently bold to render the belt useless because of marking of the paper being formed on the belt. This advantage is due to the fact that the terminal warp ends are spaced further apart along a given zone as the number of zones in the seam increased. The terminal ends of the various warps terminating along a particular zone of the three zones in the three-warp pattern seam are separated by only two warps, and a hole developing at one terminal end can sometimes propagate to its neighboring terminal warp end and thereafter propagate even further along the zone in what may be termed a chain reaction. In the four, five, six, seven and eight zone seams of examples 1-5, however, an extra separating warp is added between each set of terminal warp ends each time the number of zones is increased by one. Due to this increase in the distance between the terminal warp ends along any specific zone, deleterious hole propagation is much less likely to occur with the seams of this invention than with the three-warp or three-row seam. This is a very important feature because any holes formed along the seam will adversely mark the paper sheet, which marking will of course be increased as the hole size becomes larger, but the seams of this invention have a substantially lesser tendency to develop elongated holes encompassing a number of neighboring warps along a particular seam zone.

The seams and fabrics in examples 1-5 used plastic monofilaments as the warps and wefts. The same seam patterns may be utilized in fabric made from metal warps and wefts, or a combination such as plastic warps and metal wefts or metac warps and plastic wefts. Where plastic materials are used for either or both the warps and the wefts, the seam strength can be increased, often by 10 percent to 30 percent, by coating the finished seen with an adhesive; this has the effect of more permanently fixing the warp ends. Suitable types of adhesives include epoxy adhesives and nitrile rubber adhesives, although other types may also be used. The adhesive is spread over the entire seam area and then allowed to dry. The warp ends which terminate along the various zones of the seams can be either snipped or chiseled in order to be cut to the proper size after they have been interwoven with the seam wefts; as between these two methods of trimming the warp ends, snipping has been found to produce slightly higher seam strengths.

The number of seam wefts which are added to the fabric in order to form the various seams should generally be at least from one to three times the number of woven wefts in the length of fabric being joined by the seam; within this operative range, from IV: to three times seems to give optimum results. A narrower seam is somewhat more difficult to assemble than a wider seam. Thus in examples 1-5, where the fabric itself had 32 woven wefts per inch, the seams ranged from 64 to 67 seam wefts wide and all seams were satisfactory for papermaking uses. The several zones of the various seams can be from one to three seam wefts wide, since it is difficult to tenninate warp ends along or adjacent the same seam weft across the entire seam. Furthermore, although it is best that the zones be approximately equally spaced so that there is about the same number of seam wefts between each zone, this equal spacing can vary somewhat within a range of one to three seam wefts.

In the description of the preceding seams, it is stated that the warps have their ends aligned to terminate along particular zones of the seam, but it is pointed out that the warp which terminates in such fashion need not be the identical warp throughout the entire length of fabric. Some warps may be trimmed to terminate at an edge of the fabric so that the fabric does not present identical warps of each end. Also, the seam may be used to join ends of two different fabrics, either-forming an extended length of fabric or a closed loop. in either event, the ends of the warps that terminate along the ends of the length of fabric parallel to the seam are to be joined along the seam wefts in the prescribed manner. The seams of this invention can be used to form belts for use as the papermaking surface of a Fourdrinier machine oras a covering for the press rolls in a paper making machine. The seamed fabric can also be put to other uses such as a conveyor belt through which a vacuum is drawn to hold paper on the belt or as a dry-forming belt to form cellulosic particles into sheets by drawing suction through the belt.

Although several specific examples of this invention have been herein described in order to illustrate the invention, it is expected that changes can be made in the described embodiments and that other embodiments of the invention can be devised. it is understood that it is intended to cover all changes and modifications of the embodiments of this invention herein illustrated and other embodiments not shown which do not constitute a departure from the true spirit and scope of this invention.

I claim:

In a seam for joining two ends of woven fabric having spaced warps interwoven with spaced wefts (hereinafter referred to as woven wefts) in a selected repeated pattern, the woven wefts and warps being crimped during the weaving of the fabric to have knuckles, which seam is of the type comprisa. a plurality of seam wefts added to the fabric after it has been woven, the seam wefts being crimped to have knuckles corresponding to the knuckles in the woven wefts andspaced from one another to correspond with the spacing between the woven wefts, and also comprisb. a plurality of three-warp patterns in which a first warp of the fabric terminates along a first zone of the seam, a second warp adjacent the first warp terminates along a second zone of the seam spaced from the first zone, and a third warp adjacent the' second warp terminates along a third zone of the seam midway between the first and second zones,

the improvement wherein;

1. two other warps terminate along the seam between each three-warp pattern, thetwo other warps being adjacent to each other;

2. said two other warps being arranged to terminate along two other zones positioned outside said first, second and third zones, said two other zones comprising a first other zone spaced from said first zone on the side thereof remote from the third zone and a second other zone spaced from said second zone on the side thereof remote from the third zone, with the spacing between the first zone and the first other zone being equal to the spacing between the first zone and the third zone, and with the spacing between the second zone and the second other zone being equal to the spacing between the second zone and the third zone; and

3. one of said other warps being arranged to terminate zones of the seam. 1

3. A seam according to claim 1 further 'comprising at least two additional other warps adacent to the other warps and arranged to terminate along a dittonalother zones positioned on alternating sides of the other zones of the scam, the number of additional other zones equaling the number of additional other warps, and said additional other warps terminating along the additional other zones in alternating fashion wherein an additional other warp terminates along an additional other zone on one side of the other zone and its adjacent additional other warp terminates along an additional other zone on the opposite side of the other zones, the spacing between all zones of the seam being equal.

4. A seam according to claim 2 further comprising at least:

two additional other warps adjacent to the other warps and arranged to terminate along additional other'zones positioned on alternating sides of the other zones of the seam, the number 1.

of additional other zones equaling the number of additional other warps, and said additional otherwarps terminating along the additional other zones in alternating fashion wherein an additional other warp terminates along an additional other zone on one side of the other zoneand its adjacent additional other warp terminates along an additional other zone on the opposite side of the other zones, the spacing between all zones ofthe seam being equal.

spaced warps interwoven with spaced wefts (hereinafter referred to as woven wefts) in a selected repeated pattern, the woven wefts and warps being crimped during the weaving of the fabric to have knuckles, which seam is of the type comprising:

a. a plurality of scam wefts added to the fabric after-it has been woven, the seam wefts being crimped to have knuckles corresponding to theknuckles in the woven wefts and spaced from one another to correspond with the spacing between the woven wefts, and also comprisb. a plurality of three warp patterns in which a first warp of the fabric terminates along a first zone of the seam, a second warp adjacent the first warp terminates along a second zone of the seam spaced from the first zone, and a third warp adjacent the second warp terminates along'a third zone of the seam midway betweenthe first and second zones; and

the improvement wherein:

l. a fourth warp terminates along the seam between each three-warp pattern; and

2. said fourth warp terminating along a fourth zone positioned on the side of the first zone opposite from:the third zone, said fourth zone being spaced from the-first zone a distance equal to the spacing between the first zone and third zone.

In a seam for joining two ends of woven fabric having 

1. In a seam for joining two ends of woven fabric having spaced warps interwoven with spaced wefts (hereinafter referred to as woven wefts) in a selected repeated pattern, the woven wefts and warps being crimped during the weaving of the fabric to have knuckles, which seam is of the type comprising: a. a plurality of seam wefts added to the fabric after it has been woven, the seam wefts being crimped to have knuckles corresponding to the knuckles in the woven wefts and spaced from one another to correspond with the spacing between the woven wefts, and also comprising; b. a plurality of three-warp patterns in which a first warp of the fabric terminates along a first zone of the seam, a second warp adjacent the first warp terminates along a second zone of the seam spaced from the first zone, and a third warp adjacent the second warp terminates along a third zone of the seam midway between the first and second zones, the improvement wherein;
 1. two other warps terminate along the seam between each threewarp pattern, the two other warps being adjacent to each other;
 2. said two other warps being arranged to terminate along two other zones positioned outside said first, second and third zones, said two other zones comprising a first other zone spaced from said first zone on the side thereof remote from the third zone and a second other zone spaced from said second zone on the side thereof remote from the third zone, with the spacing between the first zone and the first other zone being equal to the spacing between the first zone and the third zone, and with the spacing between the second zone and the second other zone being equal to the spacing between the second zone and the third zone; and
 3. one of said other warps being arranged to terminate along the first other zone and the second other warp being arranged to terminate along the second other zone.
 2. said fourth warp terminating along a fourth zone positioned on the side of the first zone opposite from the third zone, said fourth zone being spaced from the first zone a distance equal to the spacing between the first zone and third zone.
 2. said two other warps being arranged to terminate along two other zones positioned outside said first, second and third zones, said two other zones comprising a first other zone spaced from said first zone on the side thereof remote from the third zone and a second other zone spaced from said second zone on the side thereof remote from the third zone, with the spacing between the first zone and the first other zone being equal to the spacing between the first zone and the third zone, and with the spacing between the second zone and the second other zone being equal to the spacing between the second zone and the third zone; and
 2. A seam according to claim 1 further comprising a third other warp adjacent the said two other warps, said third other warp being arranged to terminate along a third other zone positioned outside one of the first and second other zones and spaced therefrom a distance equal to the spacing between the zones of the seam.
 3. A seam according to claim 1 further comprising at least two additional other warps adjacent to the other warps and arranged to terminate along additional other zones positioned on alternating sides of the other zones of tHe seam, the number of additional other zones equaling the number of additional other warps, and said additional other warps terminating along the additional other zones in alternating fashion wherein an additional other warp terminates along an additional other zone on one side of the other zone and its adjacent additional other warp terminates along an additional other zone on the opposite side of the other zones, the spacing between all zones of the seam being equal.
 3. one of said other warps being arranged to terminate along the first other zone and the second other warp being arranged to terminate along the second other zone.
 4. A seam according to claim 2 further comprising at least two additional other warps adjacent to the other warps and arranged to terminate along additional other zones positioned on alternating sides of the other zones of the seam, the number of additional other zones equaling the number of additional other warps, and said additional other warps terminating along the additional other zones in alternating fashion wherein an additional other warp terminates along an additional other zone on one side of the other zone and its adjacent additional other warp terminates along an additional other zone on the opposite side of the other zones, the spacing between all zones of the seam being equal.
 5. In a seam for joining two ends of woven fabric having spaced warps interwoven with spaced wefts (hereinafter referred to as woven wefts) in a selected repeated pattern, the woven wefts and warps being crimped during the weaving of the fabric to have knuckles, which seam is of the type comprising: a. a plurality of seam wefts added to the fabric after it has been woven, the seam wefts being crimped to have knuckles corresponding to the knuckles in the woven wefts and spaced from one another to correspond with the spacing between the woven wefts, and also comprising; b. a plurality of three warp patterns in which a first warp of the fabric terminates along a first zone of the seam, a second warp adjacent the first warp terminates along a second zone of the seam spaced from the first zone, and a third warp adjacent the second warp terminates along a third zone of the seam midway between the first and second zones; and the improvement wherein: 